This application claims the benefit of the Korean Application No. P2002-43609, filed on Jul. 24, 2002, which is hereby incorporated by reference.
1. Field of the Invention
The invention relates to a method for controlling operation of a refrigerator, and more particularly, to a method for controlling operation of a refrigerator compressor.
2. Background of the Related Art
A refrigerator is used for the long time fresh storage of food. In general, the refrigerator is provided with a food storage chamber for storing food in a frozen, or refrigerated state, and various components for carrying out a refrigerating cycle to cool down the food storage chamber. Among the key components for carrying out a refrigerating cycle, there are a compressor for compressing the refrigerant, a condenser for isobaric condensing of the compressed refrigerant, an expanding device for adiabatic expansion of the compressed refrigerant, and an evaporator for isobaric evaporation of the expanded refrigerant.
In the meantime, the refrigerator cools down the food storage chamber as the refrigerant circulates through the compressor, the condenser, the expanding device, the evaporator, and the compressor in succession. Once the food storage chamber is cooled down below a preset temperature as the compressor is driven for a time period, the compressor is stopped to stop circulation of the refrigerant, to stop the cooling down of the food storage chamber. If the compressor is stopped for a certain time period, the temperature of the food storage chamber rises, and if the temperature of the food storage chamber rises above a preset temperature, the compressor comes into operation, to cool down the food storage chamber again.
FIGS. 1 and 2 illustrate graphs each showing an example of a method for controlling operation of a compressor in a related art refrigerator carried out as above. Related art methods for controlling operation of a compressor in a refrigerator will be explained, with reference to FIGS. 1 and 2.
Referring to FIG. 1, the compressor is controlled to turn on/off repeatedly so that the temperature of the food storage chamber is within preset upper/lower temperature deviations (hereafter called as xe2x80x9cxcex94Txe2x80x9d) from a preset optimal set temperature (hereafter called as xe2x80x9cTxe2x80x9d). That is, when the temperature of the food storage chamber reaches to an upper limit of Txc2x1xcex94T, the compressor is turned on to drop the temperature of the food storage chamber, and when the temperature of the food storage chamber reaches to a lower limit of Txc2x1xcex94T, the compressor is turned off to leave the temperature of the food storage chamber to rise, thereby controlling the temperature of the food storage chamber to be within Txc2x1xcex94T. In this instance, the xe2x80x9cTxe2x80x9d is required for prevention of the compressor from being turned on/off too frequently.
In more detail, referring to FIG. 2, in the related art, a method for controlling turn on/off the compressor is used so that the temperature of the food storage chamber is to be within Txc2x1xcex94T according to the upper/lower temperature deviations xcex94T (1) fixed regardless of an external temperature variation with reference to an optimal set temperature xe2x80x98Txe2x80x99 required at the food storage chamber.
Consequently, while the turn on/off time period 2 is the shortest when an outside temperature is at a standard temperature (a temperature in a range of 20xc2x0 C.xcx9c30xc2x0 C.); the turn on/off time period is long when the outside temperature is higher or lower then the standard temperature because the turn off time period 4 of the compressor is long when the outside temperature is lower than the standard temperature owing to a reduced heat load of the refrigerator, and the turn on time period 3 of the compressor is long when the outside temperature is higher than the standard temperature owing to an increased heat load of the refrigerator.
In the meantime, xe2x80x98Txe2x80x99 is inversely proportional to a freshness of food. That is, the higher the xe2x80x98Txe2x80x99, the lower the freshness of the food because the temperature of the food storage chamber varies in a great range with reference to xe2x80x98Txe2x80x99, and the lower the xe2x80x98Txe2x80x99, the higher the freshness of the food because the temperature of the food storage chamber varies in a small range with reference to xe2x80x98Txe2x80x99.
However, as explained, setting the xe2x80x98Txe2x80x99 too low for improvement of the freshness of the food causes too frequent turn on/off of the compressor, that degrades performance and lifetime of the compressor.
Accordingly, the present invention is directed to a method for controlling operation of a refrigerator that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.
An object of the present invention is to provide a method for controlling operation of a refrigerator, which can improve freshness of food stored therein while performance and lifetime of a compressor thereof are improved.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, the method for controlling operation of a refrigerator including the steps of turning on a compressor when a temperature of a food storage chamber reaches to an upper limit of upper/lower temperature deviations xcex94T from an optimal setting temperature T, turning off the compressor when the temperature of the food storage chamber reaches to a lower limit of upper/lower temperature deviations xcex94T from the optimal setting temperature T, and varying the upper/lower temperature deviations xcex94T with an outside temperature.
The variation of the upper/lower temperature deviations xcex94T for a range of the outside temperature higher or lower than a standard temperature (a temperature set between 20xc2x0 C.xcx9c30xc2x0 C.) is set smaller than the variation of the upper/lower temperature deviations xcex94T for a range of the outside temperature at the standard temperature.
The variation of the upper/lower temperature deviations xcex94T for a range of the outside temperature higher or lower than a standard temperature range (a temperature range of 20xc2x0 C.xcx9c30xc2x0 C.) is set smaller than the variation of the upper/lower temperature deviations xcex94T for a range of the outside temperature at the standard temperature.
The upper/lower temperature deviations are set such that the turn on/off period of the compressor is maintained constant regardless of the outside temperature.
The method further includes the step of making realtime monitoring of the turn on/off period of the compressor, and finding optimal upper/lower temperature deviations which can maintain the turn on/off period of the compressor constant and setting to a microcomputer.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.